Ecological surveillance of mosquitoes and insecticide resistance of Culex pipiens pallens in Changzhou in 2022

TIAN Cheng; CHEN Anxi; CAO Gan; LYU Xufeng

doi:10.19821/j.1671-2781.2025.04.007

Abstract：Objective To analyze the species composition,density,seasonal fluctuations,and resistance of Culex pipiens pallens to commonly used insecticides in Changzhou in 2022,so as to provide a basis for mosquito control and insecticides use in the region.Methods Mosquito ecological surveillance was conducted using the light trapping method in five habitats(residential areas,parks,hospitals,farmhouses,and livestock sheds)in Changzhou.Insecticide resistance of Cx.pipiens pallens was determined by adult mosquito contact tube method.Results In 2022,a total of 2 153 female mosquitoes were captured in Changzhou,with the average density of 4.04 mosquitoes/(light·night).Cx.pipiens pallens accounted for the highest proportion(37.30%),followed by Cx.tritaeniorhynchus(25.08%).The highest density was in livestock sheds[5.71 mosquitoes/(light·night)]and the lowest was in hospitals[2.59 mosquitoes(light·night)].The dominant mosquito species in residential areas,parks,hospitals,and farmhouses were Cx.pipiens pallens,and the dominant species in livestock sheds was Cx.tritaeniorhynchus.The mosquito density curves in residential areas and livestock sheds showed a bimodal pattern,with peaks in June and August,while the other habitats showed a unimodal pattern,with peak in June.Cx pipiens pallens showed possible resistance to propoxur and malathion,with 24-hour mortality rates of 90.65%and 89.47%,and showed resistance to beta-cypermethrin and deltamethrin,with 24-hour mortality rates of 42.50%,58.88%,respectively.Conclusion The mosquito density in rural areas of Changzhou is higher than that in urban areas.Cx.pipiens pallens is the dominant mosquito species.And adult Cx.pipiens pallens have developed resistance to pyrethroid insecticides.Insecticides should be used scientifically and rationally to delay the development of resistance.